Amplifying comparator with differential screw



July 22, 1952 Filed April 27. 1950 l. 'r. WEDIN 2,603,876

AMPLIFYING COMPARATOR WITH- DIFFERENTIAL SCREW 3 Sheets-Sheet l I I7 36I 4 mm W 6 ..I...| A... I I 44 'ZINVENTOR.

WAR 1'. EDIN. BY

A TTORNE.Y

July 22, 1952 T. WEDIN AMPLIFYING COMPARATOR WITH DIFFERENTIAL SCREWFiled April 27, 1950 INVENTOR. IVAR T. wen/AL July 22, 1952 1. T. WEDIN2,603,876

AMPLIFYING COMPARATOR WITH DIFFERENTIAL SCREW Filed April 27, 1950 3Sheets-Sheet 5 INVENTOR. IVAI? T. web/N.

A TTO RNEK Patented July 22, 1952 2,603,876 7 7 AMPLIFYING COMPARATORWITH DIFFERENTIAL SCREW Ivar T. Wedin, Earmington, Mich., assignor ofone-half to Gertrude Wedin, Farmingtcn, Mich.

Application April '27, 1950, Serial No. 158,523

' C1aims. (ores-447) This invention relates to gages and moreparticularly to an amplifier gag construction.

It'is the object of the present gage construction 'to provideanextremely accurate measuring device, which will give'readi gs ifdesired within a millionth of an inch.

Itis' the further object' of this invention to provide an extremelysimplified amplifier gage con- ;struction which is durable, andinexpensive to manufacture.

These and other objects will be seen from'the following specificationand claims in conjunction with the appended drawingsin which: Fig. l'isa front-elevational view of the present amplifier gage.

Fig. 2 is an elevational section taken on line 2-2 or Fig. 1. I I

Fig. 3 is'a plan section taken on lin 33 of Fig.2;and

Fig. 4' is a fragmentary elevational section taken on line 4 -4 of Fig.2. M

It will be understood that the above drawings illustrate merely apreferred embodiment of the invention'and that other embodimentsarecontemplated within the scope of the claims hereafter set out.

Referring to the drawings the amplifier gage includes the hollow base llupon which is mounted the bottom anvil I2, and which is secured to saidbase by the screw l3 which projects upwardly thereinto.

Upon the opposite end of said base and through its rear portion l5upwardly projects the tubular standard [4 having a suitable cap l5.Laterally extending bracket [6 with tubular supporti g-collar i1 is'radjustably mounted upon said standard'jwith-said collar fitting aroundthe same,

.and including the bifurcations I 8: whereby said :bracket may be;secured at any desired adjusted .pos i-tion uponsaid standard. by meansof the screw!!! and the-knob 20therefor. 1

By this constructionthe bracket I6 may be manually raised and loweredand then secured in the desired position by said knob and screw. On

.the other hand the bracket l6 may be raised and lowered .by manualrotation of the hand wheel 21 secured upon the upper end of the axialshaft 2 I supported within standard [4.

, Said shaft includes a central threaded portion 22, the lower end ofsaid shaft extending into disc 23 .within saidstan'dard. The upper endof shaft 2| extends through the disc 24 and carries a bearing plate, 25,suitable ball bearings 26 being interposed between, said 'fpla'te ,and,said disc.

Threaded nut '28 is mounted upon threaded shaft 22, and transverse shaft29, is joined at one end to said nut with its opposite end projectingthrough the longitudinal slot 30 of standard [4 and terminating withinthe annular slot 3| formed upon the interior'of bracket element ll. Bythis construction rotation-of the wheel 21 will cause verticaladjustments of the nut 28 as well as the'collar'l'l which'is securedthereto by the shaft29.

' Referring to Fig. 2 there is provided a transverse bore 32-adjacentthe outer end of bracket l6 within which is positioned the guide bushing33, secured to said bracket bythe screws'34.r--

Bushing 33 is interiorally threaded at 35- by threads ofapredeterminedpitch such as a pitch or 40 threads to the inch, forillustration. The upper cylindrical portion 36 of said bushing has anelongated slot 31 therein to cooperatively receive the inner endof'theset screw 43 hereafter described.

Elevating screw 38 is positioned through said bracket and bushing andincludes a threaded portion 39 of the same pitch 1. e. a 40pitch, for

example, which threadedly engages bushing threads35. Spaced from threads39-there is'also provided within the elevating-screw 38 the secondthreaded portion 40, which are of a predetermined pitch whichdifiersfrom the pitch of the threads'39psaid latter threads 40 being ofa pitch for the purpose of'illustratic-n. Furthermore the hollow topanvil 42 is interiorly I threaded at 4! with the threads of the samepitch whereby said anvil threadedly engages the upper end of theelevating screw-and is adapted for ver- '38 as by the set screws 45. Byemploying a relatively large hand wheel having a 10 inch diameter forexample, it is clear that one rotation of said hand wheel through 360will cause a peripheral movement of approximately 31.4 inches. As shownin Fig. 1 the outer peripheral wall ofsaid hand wheel is suitablycalibrated at 46, v

The guide tube slidably extlids th rdllgh elevating screw 38and itsupper reducedend 48 set screw 53, said contact point being adapted-2'for cooperative engagement with thework-piecee 64 which as shown in Fig.2 rests uport'b'ottomanvil l2.

Horizontal arm 54 projects 'eutwardlyirom the? outer end of the bracketI'd-and carriesupon-its" outer end the optical glass: 552whichfincludes;vertical hair-line 55', said glass being arranged anvil 42 as well asthe top anvil stem 50. -the-. sam-e-time, however, counter-clockwiserotationofisaid screw will effect a non-rotative down- In operation thecontact 52 will, when engaging the surface of the gage 63, give areading through the needle 62, and with the gage removed and thework-piece substituted, the same pressure will be attained between thecontact 52 and the work-piece when the needle 62 again gives the samereading.

In operation itrwill bea'seen that counter-clockwiserotationofthehandwheel '44'Wi1l cause the elevating screw 38 to rise, carrying withit top At ward movement of the top anvil 42. As the th reads Mrand-9wareof different pitch, it is apparent that -the"-longitudinal movement ofthe stem-.511 ldue toa. rotary movement of the hand wheel 44 throughout360, will equal in inches outwardly of the wheel 44 adjacent itscalibrations A 46, to thereby ascertaintthe extent that the wheel MZiSrhtalt'dbeingno' aifraction offaz'rcomplete revolutiomi 2 m makingmthsimmer-mm the am-efor =1gaging.azo'peraltionziiii'is n'ecessary'to?attain a: zemi readingi wit'lt irespectstos a; precision: ga e blockwhich is 'of :arpredeterminecti'exact@dimensioni as for instance a:oneshalfiinbhigage :block,

m: the caseiwliere a'icylindri'cal'fobject is. specified to have adiameter of one-half inch..

- Initially the bracket: If is: lowered: imanually until theicontact 52isrcloseetoi the igagetblock- 63 shown: in. 2; saids gage:beingimovedgto the central: positioni: occupied-rhyme :workpiece 64.

Then the hand whe e1? 44 is'rotated manualhg causing?a::doivnwardiverticalrzmoyement of themstem .501.

il 'contactf 525 engages; thEItODLSLHfGsCEFOf gageibldcle .6 3:When'athis is:done;i ti mn 'essary: toe-take aL'Ireadingoffthe:calibrations 4'6,

which would sber-the'. zeroiireadinggi afterrwhich the hand wheel 44would be turnedzslig'htlyi'in the opposite direction toelevateathetwcontact semen sufilcienthi toz'pennit'withdrawar of :the

* 'l'l'iereaf t'er methane wheel-4.41s rotated' mane oppositedirectionfcausmg downward-rmovement of the contact 52 zunti'l' thesamecengagesrthextop or the work-piece jafteiiwhiclranotherreading istaken" f the= calibrations: .463. The fdifference between; the twoireadings sot the-calibration il any; will indicate: the variance; ofidimension of the work-' piece'fronrthe gagerblock 63:

= In'attaininggreati accuracy; "as'is the casewith the presentamplifieicgage; .there must bearrassirrancethat -the: contact-52"engages the gage bl'oclt as: well as the worlc-piecei 64 2 a1;the-isame predetermined pressurecz. .fI-his isattaine'd byemploying the:floating niotmting. for: the upper-"end of the stem 50 wherebiy thepressure of: engagemen-t of bontacfi 'dzi'is :iiransinittedtorthe-upperend- 6f the stentfill and thence to: theindicator 56. I i-rsaidilldicfiitcthayail'biflllfbated 'pflrtion: 11F911 itsf-rear portion.permitting :a:swivel mountingg-at 51 upon the upper end of the support58;'.-the

lowerii end-pf: said support' being wsecuredeat 59 tostheatohzanvilAZ:

1 f Actuarhorfi I "under a predetenninedaspring Ttensicnz-orTorrepound;--for instance; proj ectsethrough the-guide; 50- and is adapted;forrcooperativeeneement -.withthe upper end of stem 50 T when contactr52.isrine engagement with: the gage-block 63'or theework-piecefi4. Asshownin Fig 1 indicator 56' is calibrated at 63 and-the needle- 62 moveswvithrespect to said calibrations responsive to mer zne t e eee e ie q H r rI .inch.

the diiference between the leads of said threads. For example in thepreferred embodiment above described; for i1lustration; -the-.1owerthreadz-was a -360-revo1ution: counter-,cloclswisewofhand-wheel 44 'iandthe =-screw- 3 8=would zcause a -longitudinal upward movement of .025inchl-z Atthe-samertime this same rotation-.-obthesscrewd 8 would ;causea:dowrnzvardi 'l'ongitudinahmovemene of the; tch

anvil42distance Ofyf.0-20;'iI1Ch;?With theereSlllt that the total upwardmovement of-the stem 5ll for one complete -revoluti-on. of the wheel. 44

would beeonlyr.005einche ".OIkfihB' otherhand a 360 rotationi-othandwvheek 4k in a .clockwise dlrection rwould :eff-ect =-a, total-longitudinal down-- ward movement of the contact 52.-equa1:-*to .005

By employing a hand wheel having-aten-inch diameter it is seen ethat at360% rotation of the same will cover approximately 31.4 inches, and

all" of: this. rotation; will.- only --pro.duce a longitudinal movementof .0Q5';inchiof,the c0ntaet52'. It will-she; apparent from: the:following schedule that ver-y :mi-nutelcngitudinal distances-maybemeasurednpon?fractienal-movementsof:thehend Longitudinal" Feed Movementif Circumference Qt Hand WheeL .005 .31'Aiiiches: (360) .001'=6;2s0inches; .0001 =-.628 inch;

Thus it is 'apparent by properly arrangingthe calibrations 46 'upon theh'and'wheel '44, amovement-'ofsaid handwheel .00628 in-one direction.

or the other past the -hair line- 55' cr me optical lens 55: would causea-- longitudinal agmgmovement of contact 52 in one direction or theother,

'one-millionth of an inchi- To attain extreme accuracyin anamplifiergageof this type it is; essential thatthe thread'sr35; 3,9 40' and 4 I ,beprecision ground. It'is possible jby using a calibrated lead screw-withzeroerror that very accurate .threads may beground'where the totalerror'oven'aninch' of thread willnotexueed .0001' inch; In. ..other--W0rds the error for. one revolutionona40pitchthreadlwould.belapproxi21am /zimillionth's .of Ian inch .per. total revoluion. 7 It iscontemplated that any suitahlep th .Q

threadbeemplayed.iior the two thyreadsiupqn the elevating screw 38,howeverit'is essential that the two lpitches be different "to therebyobtain a difierential movement of the stem 5|] upona rota'ry movement ofsaid screw.':: 'For instance it might be'desira'ble that one of thethreads-have a 'pitch' or lead of .025 inch and the other" thread wouldhave a pitch or lead of .026 inch; This would mean for one completerevolution of hand wheel 44 the total gaging movement of the contact 52would be only ,001 inch, and this corresponds to a circumference ofrotation of approximately 31,4 inches. By rotating said hand wheelthrough a circumference of 3.14 inches the gag-,- ing movement would be.0001 inch, similarly, a rotary movement of .314 inch would cause agaging movement of .00001 inch, and finally a retary movement of .0314inch which is visible, being approximately of an inch, would cause agage movement of contact 52 equal to .000001 inch, i. e. one-millionthof an inch.

Having described my invention, reference should now be had to the claimswhich follow for determining the scope thereof.

Iclaim:

1. An amplifier gauge comprising a base including a work-piecesupporting bottom anvil, an upright standard on said base, an outwardlyprojecting bracket adjustably mounted upon said standard, a hollowrotatable elevating screw having a thread of predetermined pitchthreaded through said bracket, a second thread on 6 loosely "throug'hfsaid stem" guide, and a handwheel mounted upon said screw, itsperipheral surface -h'aving' a pre-determined calibration thereontoyisiblyindicate the variation in height of i a work pieee' with-respect toa gage block initially contacted by saidstem. -3.'* Anamplifier 3 gauge comprising eluding a work-piece supporting bottomanvil, an upright standard'on said base, an outwardly projecting bracketadjustably mounted upon said standard, a hollow rotatable'elevatingscrew havinga-thread of predetermined pitch threaded through saidbracket, a second thread on said screw-spaced fromsaid first thread andhaving a different predetermined pitch, a top anvil mounted upon" and inthreaded engagement with said second :thread; guide means loosely in-.terconnecting said bracket and top anvil to prevent rotation thereof, astem joined to and desaid screw spaced from said first thread and havinga different predetermined pitch, a top anvil mounted upon and inthreaded engagement with said second thread, guide means looselyinterconnecting said bracket and top anvil to prevent rotation thereof,a stem joined to and depending from said top anvil with its lower endcooperatively engageable with a workpiece upon said bottom anvil,whereby rotation of said screw will effect a differential longitudinalmovement of said stem, and a tubular stem guide joined to and dependingfrom said top anvil and slidable through said screw, said stem extendingloosely through said stem guide, and a handwheel mounted upon saidscrew, its peripheral surface having a pre-determined calibrationthereon to visibly indicate the variation I in height of a work-piecewith respect to a gage block initially contacted by said stem.

2. An amplifier gauge comprising a base including a work-piecesupporting bottom anvil, an upright standard on said base, an outwardlyprojecting bracket adjustably mounted upon said standard, an uprighthollow rotatable elevating screw having a thread of predetermined pitchthreaded through said bracket, a second thread on said screw spacedabove said first thread and having a different predetermined pitch, atop anvil mounted upon and in threaded engagement with said secondthread, guide means loosely interconnecting said bracket and top anvilto prevent rotation thereof, a stem joined to and depending from saidtop-anvil with its lower end cooperatively engageable with a workpieceupon said bottom anvil, whereby rotation of said screw will effect adifferential longitudinal movement of said stem, and a tubular stemguide joined to and depending from said top anvil and slidable throughsaid screw, said stem having a transverse slot at its upper end, and apin extending through said top anvil, said guide, and through said slotproviding a floating connection with said top anvil permitting relativemovement therebetween, said stem extending pending from said'topanvilwith' its lower end cooperatively engageable with awork-pieceupon said bottom anvil, whereby rotation of saidscrew willeffect a differential longitudinal movement of said stem, a tubular stemguide joined to and depending from said top anvil and slidable throughsaid screw, said stem having a transverse slot at its upper end, and apin extending through said top anvil, said guide, and through said slotproviding a floating connection with said top anvil permitting relativemovement therebetween, and a pressure indicator supported upon said topanvil and having a spring loaded moveable element cooperativelyengageable with said stem to indicate a predetermined gauging pressurebetween the lower end of said stem and said work-piece, said stemextending loosely through said stem. guide, and a handwheel mounted uponsaid screw, its peripheral surface having a pre-detennined calibrationthereon to visibly indicate the variation in height of a work-piece withrespect to a gage block initially contacted by said stem.

4. An amplifier gauge comprising a base including a work-piecesupporting bottom anvil, an upright standard on said base, an outwardlyprojecting bracket adjustably mounted upon said standard, a hollowrotatable elevating screw having a thread of predetermined pitchthreaded through said bracket, a second thread on said screw spaced fromsaid first thread and having a different predetermined pitch, a topanvil mounted upon and in threaded engagement with said second thread,guide means loosely interconnecting said bracket and top anvil toprevent rotation thereof, a stem joined to and depending from said topanvil and extending longitudinally through said screw with, its lowerend cooperatively engageable with a work-piece upon said bottom anvil,whereby rotation of said screw will effect a differential longitudinalmovement of said stern, and a hand wheel mounted upon said screw, its,peripheral surface having a predeter mined calibration thereon tovisibly indicate the variation in height of a work piece with respect toa gage block initially contacted by said stem.

5. An amplifier gauge comprising a base in- I eluding a work-piecesupporting bottom anvil, an upright standard on said base, an outwardlyprojecting bracket adjustably mounted upon said standard, an uprightbushing extending through said bracket and secured thereto, and havingan upright longitudinal slot formed therein, a hollow rotatableelevating screw having a thread of predetermined pitch threaded throughsaid bushing, a second thread upon said screw spaced a base in-

